Too late to edit, so here is one further clarification : the above example is not only time coherent, but also time coincident. Big difference.
Every time coincident system is also time coherent; the reverse, rarely.
Not. Phase coherence is the location of voice coils on one axis. Phase linearity is its graph that does not cross the 0-axis. But in any case, the good / bad crossover will greatly affect the phase curve.
And the result will be a group delay time of the signal and if this indicator is within 1-2 milliseconds, then it is impossible to determine by phase a coherent and ordinary speaker.
And besides this, the exact distance of the left / right speakers to the listener is very important.
Funny
Cause that was my point...the whole prosound sector (commercial), has decided phase coherency is important. A sector with huge R&D budgets and testing facilities.
And an extremely competitive sector where brand loyalty and ownership ego, barely exists.
And they are all, without exception afaict, touting phase coherency.
Either for the simple sonic benefit to a single speaker, or the ability to manipulate phase for line array pattern control, or the emerging immersive sound / acoustic space sculpting market.
The scope of technological change and product development is amazing to me, honestly it makes home audio seem stuck in the mud. Maybe that's my big underlying point Lol
Some folks strongly prefer academic studies and theoretical discussions to prove points. Trying to eliminate bias. Cool.
Makes for good product designs/ good recipes.
But still, the proof is in the pudding...the product itself....so commercial information doesn't bother me (as long as I can ignore marketing! )
"we are able to realize very smooth frequency response for stunning clarity and sound imaging without phase distortion."
You seem to see the sentence mentions nothing about the effect of phase,
while i see yamaha saying they were able to eliminate the usual phase distortion.
Funny again... I guess we both read into something what we want to see..
Read threads about Danley Synergy or Unity horns
The Danley-invented Unity and its upgrade, the Syngery, are claimed to be very phase correct, a virtual point source. Elsewhere there are threads about time aligning of drivers, which is related to phase. I am a happy user of a sort-of bastard Danley system, the Yorkville U15 Unity. Mine came used (trashed) and I always active EQ-ed them. With DSP (JRiver Media Center), and REW, I have them EQ-ed and timing corrected, within my limited testing powers. They are easily the most realistic imagining speakers I ever have owned, and I've had many (not horns though). Much of my material is 128K MP3 or its streamed equivalent. Most things sound wonderful. Surely this impression is not entirely due to the effects of cannibis herb.
The Danley-invented Unity and its upgrade, the Syngery, are claimed to be very phase correct, a virtual point source. Elsewhere there are threads about time aligning of drivers, which is related to phase. I am a happy user of a sort-of bastard Danley system, the Yorkville U15 Unity. Mine came used (trashed) and I always active EQ-ed them. With DSP (JRiver Media Center), and REW, I have them EQ-ed and timing corrected, within my limited testing powers. They are easily the most realistic imagining speakers I ever have owned, and I've had many (not horns though). Much of my material is 128K MP3 or its streamed equivalent. Most things sound wonderful. Surely this impression is not entirely due to the effects of cannibis herb.
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Filter theory covers that.
It says that a filter does phase change at a certain stage
Odd order filters do 270° and 90° and equal order 180° and
360° ( I didn't know that with cascaded 2nd order filter you lose a full period)
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Hi and thank you very much for the very helpful and interesting advice.
I usually listen perfectly on-axis with speakers and actually to lower the influence of the listening room i am looking to horn speakers with limited/controlled dispersion and also i like the low distortion usually provided by such drivers.
I have a further question ... can coaxial drivers provide any advantages phase wise ? drivers like Tannoy dual concentric i mean.
Hi thanks for the valuable advice. I understand the time thing ... if we consider a two way speaker the emission from the woofer should reach the listening spot at the same time of that from the tweeter ... and this i guess can be achieved by mounting the tweeter and the woofer coils on a same plane. This is clear to me. (Adding also the delay caused by the xover of course)
Here an example of a pretty time coherent speaker if i understand well.
https://www.stereophile.com/images/archivesart/1205lip1.jpg
But the phase is a mess. For instance i do not understand why they have connected in the same speaker above the TW out of phase with the WF ??? the tweeter peak goes down and the woofer peak goes up ???
https://www.stereophile.com/images/archivesart/1205lipfig.7.jpg
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Hi ! are you referring to room reflections ? this is the very usual issue in a not treated listening room like mine. And actually i read somewhere that for this situation is better to look at speakers with a narrow dispersion
Thank you very much indeed. I think you have offered me the solution. I am quite convinced now that coaxials/horns are the way to go for me.
I am starting now to study the topic. Speaking of coaxials i have listening to Tannoy models and they were at least nice sounding.
Which kind of speaker do you like best ?
do you have a pic for this arrangement ? and moreover how is it possible to add delay in a passive xover ? i had one active and there is a pot for this very convenient ... maybe i do not understand why some xover delay the woofer ??? usually the woofer is more distant/behind than the mid-high section.
In conclusion ... are coaxials and horns the very way to go ? i am very interested and if this is the case i will go to the relevant section
Thanks a lot again.
Kind regards,
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I am unsure if narrow dispersion by itself fixes the phase issues. Inconsistent off-axis response results in 'head-in-a-vice' soundstage, which is not my preference.
The old Tannoys were magnificent. Not sure of the newer ones. They seem to have lost something over time. Coaxials also have issues of inconsistent FR and most manufacturers tend to cross them quite high for domestic use (to keep directivity loss small, I think).
I like wideband drivers doing 200-4k with support at both ends. Trouble is this means a 4" driver, and finding one good enough is tough. The FU10RB and the Scan wideband are good, but still lack distortion performance compared to good Satoris when playing loud. BG makes some ribbons that can get close to this target. My personal speakers use a Satori MW13P" from 250 to 2.3k, with a ring dome above and a Volt B2549 woofer below it.
No I don't, these are theoretical simulations.
Delay in passive crossovers are implemented using all-pass networks and yes, it is possible. Zaph's ZD5 uses this kind of arrangement to time align the tweeter.
Delay for woofer may be used when some horn speakers have the tweeter behind the woofer due to the throat of the horn.
RCF has some nice coaxials that you could look at. I believe there's some innovations in the pro space on horn design, that help cross closer to realistic frequencies when using large woofer.
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i read the same ... the exec quality of the older units is much superior ... even alnico magnets
Many recent drivers have plastic cones instead of paper. Plastic cones tend to sound less crisp ... less transparent.
But still the concept is the same. I have some cheaper Tannoy DC drivers to work on.
I will study more on the topic.
one problem is that the cone of the woofer acts like an horn for the tweeter and is continuosly moving back and forth ... not the best horn possible i understand
some coaxials instead employ a fixed horn for the tweeter.
https://www.picclickimg.com/d/l400/...-604-8k-604-Speaker-post-Western-Electric.jpg
Very very interesting and great drivers indeed.
Speaking of 3 ways i am always been uncertain about which mid to use.
I can see used both cone e dome mids.
I really do not know where a xover cut can make less damage ...
Still undecided. I think i will do with just two ways ...
thanks a lot. I am afraid is too complicated for me. I am leaning towards active crossing ... two ways ... big coaxial ... maybe even adding digital eq
I see passive xovers as a very big tech challenge, both for design and construction as well.
And they can be very expensive when quality parts are used.
I will look immediately at their catalogue then ... good old Tannoys have reached a cult status and cult prices as well. Out of reach.
I see coaxial speakers in my future
Thank you so much again
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I managed to add a tweeter and make it a three way
Americans just like to stress on the bass. No other arguments...bass extension, power bla bla bla
a 3 way crossover! What else ? Being the woofer a 4" ( seas RCy) the midbass point is set to 7-800 Hz...and being the tweeter a Dayton AMt mini-8, the mid/treble XO is set to 10000 Hz
( and being the midrange a Whisper from Aurasound...:rolleyes )
All 12 dB/oct
According to Blauert & Laws (1978), it takes 2ms of group delay to be audible at 1kHz. A LR2 filter may produce 300μs. Phase changes 180 degrees.
I didn't suggest this. There are several reasons. One is that chopping your baffle can produce delayed diffraction.. If you put your tweeter back 25mm it saves only 70μs. You can make up this difference in your crossover.
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Hi ! thank you very much indeed for the very helpful information.
So in the end this coherency can be measured ... good. I guess the delay is obtained placing different drivers on different planes
Thanks again My feeling is that to have high coherence is good anyway.
Both of time and phase.
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